1. Field Of The Invention
The present invention relates generally to methods and apparatus for incinerating combustible wastes, and more particularly, to improved methods and apparatus for accumulating and conveying the hot ash continuously produced in an incineration system.
2. Description of the Prior Art
The incineration of solids such as municipal refuse produces hot ash which must be accumulated, cooled and conveyed from the incineration system to a point of disposal. A commonly utilized incineration system includes a wastes incinerator, such as a rotary kiln, wherein the wastes are combusted to produce combustion gases and hot ash. The hot ash is conducted by gravity from the kiln to associated accumulating and conveying apparatus.
Various types of accumulating and conveying apparatus have been utilized heretofore. One such prior art apparatus is comprised of a water tank having a slanted side. A chain conveyor system is mounted within the tank against the slanted side for collecting ash which is dropped into the tank and water contained therein from the wastes incinerator. The hot ash is quenched by the water and then settles to the bottom of the tank from where it is conveyed up the slanted surface of the tank and into a disposal hopper, another conveyor or the like.
A variety of problems are encountered in the use of ash accumulating and conveying apparatus of the type described above. While the water tank is generally arranged with respect to the incinerator to provide a liquid seal which prevents air infiltration into the incinerator, the hot ash causes steam to be produced which backflows into the incinerator reducing its efficiency. The steam also causes slag to build up in both the incinerator and the ash handling apparatus. In addition, such water tank conveying systems readily break down as a result of the abrasive and non-uniform nature of the ash.
Another prior art ash accumulating and conveying system utilizes one or more valves in association with a conveyor. The hot ash from the incinerator flows by gravity through a conduit to a valve and is allowed to build up thereon. The valve is periodically opened whereby the ash falls therefrom onto a conveyor or onto a second valve. When a second valve is used, the top valve is closed followed by opening of the second valve to minimize air infiltration to the incinerator. However, even where two valves are used, air leakage into the incinerator takes place causing disruptions in the incinerator operation. In addition, the heat transferred to the valves from the hot ash causes distortion of the valve seats and other parts which along with the abrasiveness of the ash produces frequent breakdowns and maintenance.
By the present invention improved methods and apparatus for accumulating and conveying hot ash in an incinerator system are provided which obviate the above-mentioned problems associated with air and/or steam infiltration to the incinerator, slag buildup, valve failures, etc.